Analysis of the Chaotic Behavior of the Lower Hybrid Wave Propagation in Magnetised Plasma by Hamiltonian Theory

The Hamiltonian character of the ray tracing equations describing the propagation of the Lower Hybrid Wave (LHW) in a magnetic confined plasma device (tokamak) is investigated in order to study the evolution of the parallel wave number along the propagation path. The chaotic diffusion of the "time-averaged" parallel wave number at higher values (with respect to that launched by the antenna at the plasma edge) has been evaluated, in order to find an explanation of the filling of the spectral gap (Fisch, 1987) by "Hamiltonian chaos" in the Lower Hybrid Current Drive (LHCD) experiments (Fisch, 1978). The present work shows that the increase of the parallel wave number $n_{\parallel}$ due to toroidal effects, in the case of the typical plasma parameters of the Frascati Tokamak Upgrade (FTU) experiment, is insufficient to explain the filling of the spectral gap, and the consequent current drive and another mechanism must come into play to justify the wave absorption by Landau damping. Analytical calculations have been supplemented by a numerical algorithm based on the symplectic integration of the ray equations implemented in a ray tracing code, in order to preserve exactly the symplectic character of a Hamiltonian flow

Potential of Energy Saving of Propane Heat Pump as replacement of gas boilers with low and high temperature emitters

This work deals with the analysis of the energy performance and the environmental impact of a Heating, Ventilation and Air Conditioning (HVAC) system based on an innovative Air-to-Water electrical Heat Pump (AWHP) using propane (R290) as the refrigerant. A building of the University of Bologna located in Forlì (North of Italy) is considered for replacing a condensing gas boiler and a conventional chiller with an AWHP using R290. To evaluate the efficiency of the existing heating system and the potential savings linked to the adoption of the propane AWHP, the building energy model was created and calibrated by collecting monthly thermal and electrical consumptions as a function of the actual climate data. In this paper, the main features of the R290-based AWHP are described in detail by emphasising the device performance as a function of the operating conditions (i.e., air and water temperature and speed of the scroll compressor). A series of scenarios have been studied to evaluate the energy performance of the propane AWHP with respect to the reference scenario under various operating conditions. The results show that while the total primary energy demand increases adopting the propane AWHP with respect to the case of a gas boiler, the non-renewable primary energy fraction decreases significantly, with a dramatic increase in the renewable quote. From an economic point of view, lower annual costs are obtained by adopting a propane AWHP coupled to fan coils, mainly when the electrical heat pump is used in a thermally insulated building in which a photovoltaic system is installed

Incidence and Determinants of Symptomatic and Asymptomatic SARS-CoV-2 Breakthrough Infections After Booster Dose in a Large European Multicentric Cohort of Health Workers-ORCHESTRA Project

Background: SARS-CoV-2 breakthrough infections (BI) after vaccine booster dose are a relevant public health issue. Methods: Multicentric longitudinal cohort study within the ORCHESTRA project, involving 63,516 health workers (HW) from 14 European settings. The study investigated the cumulative incidence of SARS-CoV-2 BI after booster dose and its correlation with age, sex, job title, previous infection, and time since third dose. Results: 13,093 (20.6%) BI were observed. The cumulative incidence of BI was higher in women and in HW aged < 50 years, but nearly halved after 60 years. Nurses experienced the highest BI incidence, and administrative staff experienced the lowest. The BI incidence was higher in immunosuppressed HW (28.6%) vs others (24.9%). When controlling for gender, age, job title and infection before booster, heterologous vaccination reduced BI incidence with respect to the BNT162b2 mRNA vaccine [Odds Ratio (OR) 0.69, 95% CI 0.63-0.76]. Previous infection protected against asymptomatic infection [Relative Risk Ratio (RRR) of recent infection vs no infection 0.53, 95% CI 0.23-1.20] and even more against symptomatic infections [RRR 0.11, 95% CI 0.05-0.25]. Symptomatic infections increased from 70.5% in HW receiving the booster dose since < 64 days to 86.2% when time elapsed was > 130 days. Conclusions: The risk of BI after booster is significantly reduced by previous infection, heterologous vaccination, and older ages. Immunosuppression is relevant for increased BI incidence. Time elapsed from booster affects BI severity, confirming the public health usefulness of booster. Further research should focus on BI trend after 4th dose and its relationship with time variables across the epidemics.BackgroundSARS-CoV-2 breakthrough infections (BI) after vaccine booster dose are a relevant public health issue.MethodsMulticentric longitudinal cohort study within the ORCHESTRA project, involving 63,516 health workers (HW) from 14 European settings. The study investigated the cumulative incidence of SARS-CoV-2 BI after booster dose and its correlation with age, sex, job title, previous infection, and time since third dose.Results13,093 (20.6%) BI were observed. The cumulative incidence of BI was higher in women and in HW aged < 50 years, but nearly halved after 60 years. Nurses experienced the highest BI incidence, and administrative staff experienced the lowest. The BI incidence was higher in immunosuppressed HW (28.6%) vs others (24.9%). When controlling for gender, age, job title and infection before booster, heterologous vaccination reduced BI incidence with respect to the BNT162b2 mRNA vaccine [Odds Ratio (OR) 0.69, 95% CI 0.63-0.76]. Previous infection protected against asymptomatic infection [Relative Risk Ratio (RRR) of recent infection vs no infection 0.53, 95% CI 0.23-1.20] and even more against symptomatic infections [RRR 0.11, 95% CI 0.05-0.25]. Symptomatic infections increased from 70.5% in HW receiving the booster dose since < 64 days to 86.2% when time elapsed was > 130 days.ConclusionsThe risk of BI after booster is significantly reduced by previous infection, heterologous vaccination, and older ages. Immunosuppression is relevant for increased BI incidence. Time elapsed from booster affects BI severity, confirming the public health usefulness of booster. Further research should focus on BI trend after 4th dose and its relationship with time variables across the epidemics

SARS-CoV-2 Breakthrough Infections: Incidence and Risk Factors in a Large European Multicentric Cohort of Health Workers

The research aimed to investigate the incidence of SARS-CoV-2 breakthrough infections and their determinants in a large European cohort of more than 60,000 health workers

Analysis of the Chaotic Behavior of the Lower Hybrid Wave Propagation in Magnetised Plasma by Hamiltonian Theory

The Hamiltonian character of the ray tracing equations describing the propagation of the Lower Hybrid Wave (LHW) in a magnetic confined plasma device (tokamak) is investigated in order to study the evolution of the parallel wave number along the propagation path. The chaotic diffusion of the “time-averaged” parallel wave number at higher values (with respect to that launched by the antenna at the plasma edge) has been evaluated, in order to find an explanation of the filling of the spectral gap (Fisch, 1987) by “Hamiltonian chaos” in the Lower Hybrid Current Drive (LHCD) experiments (Fisch, 1978). The present work shows that the increase of the parallel wave number $n_{\parallel}$ due to toroidal effects, in the case of the typical plasma parameters of the Frascati Tokamak Upgrade (FTU) experiment, is insufficient to explain the filling of the spectral gap, and the consequent current drive and another mechanism must come into play to justify the wave absorption by Landau damping. Analytical calculations have been supplemented by a numerical algorithm based on the symplectic integration of the ray equations implemented in a ray tracing code, in order to preserve exactly the symplectic character of a Hamiltonian flow

The Design of Experiment as a Tool to Model Plant Trace-Metal Bioindication Abilities

Bioindicator plants are species that have the capacity to linearly uptake some elements (metal and metalloids) from the growing substrate, thus reflecting their concentration in the soil. Many factors can influence the uptake of these elements by plants, among which is the simultaneous presence of several metals, a common situation in contaminated or natural soils. A novel approach that can be used to validate the bioindication ability of a species growing on a polymetallic substrate is the design of experiment (DoE) approach. The aim of the present study was to apply the DoE in full factorial mode to model the Cu, Cd, Pb, Zn, and Cr bioindication capacity of Polygonum aviculare, used as the model plant. The results showed that P. aviculare has the ability to bioindicate Cd and Cr with a linear uptake (from 0.35 to 6.66, and 0.1 to 3.4 mg kg−1, respectively) unaffected by the presence of other metals. Conversely, the uptake of Pb, Cu, and Zn is strongly influenced by the presence of all the studied metals, making their concentration in the plant shoot not proportional to that of the soil. In conclusion, these preliminary results confirmed that the DoE can be used to predict the bioindicator abilities of a plant for several elements at the same time and to evaluate the interactions that can be established between variables in the growing medium and in the plant itself. However, more studies including other plant species are needed to confirm the effectiveness of this method

Toxic metals in Camilla sinensis: Analytical Methods, Human Health Risk and Regulations

Persistent toxic substances tend to accumulate in the environment owing to anthropic activities, causing increasing detrimental to food safety. Toxic metals are among the most deleterious pollutants because they concentrate in all environmental matrices, in particular those involved in the food chain where the consequences on human health may be irreversible. Nutritional supplements, including herbal extract, vitamins, mineral salts, botanical remedies, are certainly an integral part of the food chain. For this reason, great attention has been focused on tea leaves (Camellia sinensis), widely used by the world's population to obtain drinks, generally by infusion. It should decidedly be emphasized that the concentration of toxic metals in tea should be under the maximum limits allowed by law. The problem is that in the international legislations, laws specifically concerning the tea do not exist. The existing laws in fact provide legal concentration limits for leafy vegetables in general, and only for a few metals. Obviously this is a problem that should be solved, above all by extending the maximum allowable concentration limits to an increasing number of toxic elements, but also by increasing the number of types of plants. Moreover, only in a few cases, regulations provide safe limits, but the analytical techniques useful to check for those limits are not indicated. The present work proposes an exhaustive focus on what are the metals of interest, and what is the state of the art about analytical methodologies suitable to detect these toxic metals in Camellia sinensis. For all metals or group of metals, various analytical techniques and procedures employed are critically discussed. Particular attention is paid to the analytical performance, in terms of accuracy and detectability. A separate section is dedicated to the analytical procedure for the determination in Camellia sinensis of new emerging anthropic toxic polluting metals: platinum group metals (platinum, palladium, rhodium, osmium, ruthenium and iridium) and thallium. This discussion would also be a stimulus to solicit International Organizations to fill the gap of the lack of strict and comprehensive laws regulating the maximum allowable concentrations for an increasing number of contaminants in this matrix, especially considering their enormous daily use

La malattia che cura il teatro

Il volume nasce dall’incontro tra artisti, studiosi, critici e operatori, chiamati a raccolta da Antonio Viganò e dalla sua compagnia Teatro La Ribalta – Accademia Arte della diversità di Bolzano, con lo scopo di avviare un confronto sul teatro, rispondendo a un ribaltamento della prospettiva: non il teatro che cura le ferite, ma «La malattia che cura il teatro». L’attenzione si concentra su pratiche, percorsi e pensieri di quanti provano a cambiare i codici del teatro, facendone un elemento di rinnovamento non solo artistico, ma soprattutto umano. Si tratta di strade che muovono dall’incontro con l’Altro e con la differenza, osteggiando la dittatura dell’Uguale e del Normale, scardinando regole e prassi consolidate. Dai contributi dei numerosi autori (Piergiorgio Giacchè, Guido Di Palma, Fabrizio Fiaschini, Stefano Masotti, Oliviero Ponte di Pino, Susanne Hartwig, Andrea Porcheddu, Alessandro Garzella, Alessandro Argnani, Rosita Volani, Thomas Emmenegger, Michela Lucenti, Gianfranco Berardi e Gabriella Casolari, Gianluigi Gherzi, Ugo Morelli), emergono testimonianze e riflessioni su quel che si fa e quel che si potrebbe (ancora) fare